1. sharedInformerFactory.Start
在controller-manager的Run函数部分调用了InformerFactory.Start的方法。
此部分代码位于/cmd/kube-controller-manager/app/controllermanager.go
// Run runs the KubeControllerManagerOptions. This should never exit.
func Run(c *config.CompletedConfig, stopCh <-chan struct{}) error {
...
controllerContext.InformerFactory.Start(controllerContext.Stop)
close(controllerContext.InformersStarted)
...
}
InformerFactory是一个SharedInformerFactory的接口，接口定义如下：
此部分代码位于vendor/k8s.io/client-go/informers/internalinterfaces/factory_interfaces.go
// SharedInformerFactory a small interface to allow for adding an informer without an import cycle
type SharedInformerFactory interface {
Start(stopCh <-chan struct{})
InformerFor(obj runtime.Object, newFunc NewInformerFunc) cache.SharedIndexInformer
}
Start方法初始化各种类型的informer，并且每个类型起了个informer.Run的goroutine。
此部分代码位于vendor/k8s.io/client-go/informers/factory.go
// Start initializes all requested informers.
func (f *sharedInformerFactory) Start(stopCh <-chan struct{}) {
f.lock.Lock()
defer f.lock.Unlock()
for informerType, informer := range f.informers {
if !f.startedInformers[informerType] {
go informer.Run(stopCh)
f.startedInformers[informerType] = true
}
}
}
2. sharedIndexInformer.Run
此部分的代码位于/vendor/k8s.io/client-go/tools/cache/shared_informer.go
func (s *sharedIndexInformer) Run(stopCh <-chan struct{}) {
defer utilruntime.HandleCrash()
fifo := NewDeltaFIFO(MetaNamespaceKeyFunc, nil, s.indexer)
cfg := &Config{
Queue: fifo,
ListerWatcher: s.listerWatcher,
ObjectType: s.objectType,
FullResyncPeriod: s.resyncCheckPeriod,
RetryOnError: false,
ShouldResync: s.processor.shouldResync,
Process: s.HandleDeltas,
}
func() {
s.startedLock.Lock()
defer s.startedLock.Unlock()
s.controller = New(cfg)
s.controller.(*controller).clock = s.clock
s.started = true
}()
// Separate stop channel because Processor should be stopped strictly after controller
processorStopCh := make(chan struct{})
var wg wait.Group
defer wg.Wait() // Wait for Processor to stop
defer close(processorStopCh) // Tell Processor to stop
wg.StartWithChannel(processorStopCh, s.cacheMutationDetector.Run)
wg.StartWithChannel(processorStopCh, s.processor.run)
defer func() {
s.startedLock.Lock()
defer s.startedLock.Unlock()
s.stopped = true // Don't want any new listeners
}()
s.controller.Run(stopCh)
}
2.1. NewDeltaFIFO
DeltaFIFO是一个对象变化的存储队列，依据先进先出的原则，process的函数接收该队列的Pop方法的输出对象来处理相关功能。
fifo := NewDeltaFIFO(MetaNamespaceKeyFunc, nil, s.indexer)
2.2. Config
构造controller的配置文件，构造process，即HandleDeltas，该函数为后面使用到的process函数。
cfg := &Config{
Queue: fifo,
ListerWatcher: s.listerWatcher,
ObjectType: s.objectType,
FullResyncPeriod: s.resyncCheckPeriod,
RetryOnError: false,
ShouldResync: s.processor.shouldResync,
Process: s.HandleDeltas,
}
2.3. controller
调用New(cfg)，构建sharedIndexInformer的controller。
func() {
s.startedLock.Lock()
defer s.startedLock.Unlock()
s.controller = New(cfg)
s.controller.(*controller).clock = s.clock
s.started = true
}()
2.4. cacheMutationDetector.Run
调用s.cacheMutationDetector.Run，检查缓存对象是否变化。
wg.StartWithChannel(processorStopCh, s.cacheMutationDetector.Run)
defaultCacheMutationDetector.Run
func (d *defaultCacheMutationDetector) Run(stopCh <-chan struct{}) {
// we DON'T want protection from panics. If we're running this code, we want to die
for {
d.CompareObjects()
select {
case <-stopCh:
return
case <-time.After(d.period):
}
}
}
CompareObjects
func (d *defaultCacheMutationDetector) CompareObjects() {
d.lock.Lock()
defer d.lock.Unlock()
altered := false
for i, obj := range d.cachedObjs {
if !reflect.DeepEqual(obj.cached, obj.copied) {
fmt.Printf("CACHE %s[%d] ALTERED!\n%v\n", d.name, i, diff.ObjectDiff(obj.cached, obj.copied))
altered = true
}
}
if altered {
msg := fmt.Sprintf("cache %s modified", d.name)
if d.failureFunc != nil {
d.failureFunc(msg)
return
}
panic(msg)
}
}
2.5. processor.run
调用s.processor.run，将调用sharedProcessor.run，会调用Listener.run和Listener.pop,执行处理queue的函数。
wg.StartWithChannel(processorStopCh, s.processor.run)
sharedProcessor.Run
func (p *sharedProcessor) run(stopCh <-chan struct{}) {
func() {
p.listenersLock.RLock()
defer p.listenersLock.RUnlock()
for _, listener := range p.listeners {
p.wg.Start(listener.run)
p.wg.Start(listener.pop)
}
}()
<-stopCh
p.listenersLock.RLock()
defer p.listenersLock.RUnlock()
for _, listener := range p.listeners {
close(listener.addCh) // Tell .pop() to stop. .pop() will tell .run() to stop
}
p.wg.Wait() // Wait for all .pop() and .run() to stop
}
该部分逻辑待后面分析。
2.6. controller.Run
调用s.controller.Run，构建Reflector，进行对etcd的缓存
defer func() {
s.startedLock.Lock()
defer s.startedLock.Unlock()
s.stopped = true // Don't want any new listeners
}()
s.controller.Run(stopCh)
controller.Run
此部分代码位于/vendor/k8s.io/client-go/tools/cache/controller.go
// Run begins processing items, and will continue until a value is sent down stopCh.
// It's an error to call Run more than once.
// Run blocks; call via go.
func (c *controller) Run(stopCh <-chan struct{}) {
defer utilruntime.HandleCrash()
go func() {
<-stopCh
c.config.Queue.Close()
}()
r := NewReflector(
c.config.ListerWatcher,
c.config.ObjectType,
c.config.Queue,
c.config.FullResyncPeriod,
)
r.ShouldResync = c.config.ShouldResync
r.clock = c.clock
c.reflectorMutex.Lock()
c.reflector = r
c.reflectorMutex.Unlock()
var wg wait.Group
defer wg.Wait()
wg.StartWithChannel(stopCh, r.Run)
wait.Until(c.processLoop, time.Second, stopCh)
}
核心代码：
// 构建Reflector
r := NewReflector(
c.config.ListerWatcher,
c.config.ObjectType,
c.config.Queue,
c.config.FullResyncPeriod,
)
// 运行Reflector
wg.StartWithChannel(stopCh, r.Run)
// 执行processLoop
wait.Until(c.processLoop, time.Second, stopCh)